Vascular disease is prevalent and often involves the development of a stenosis within a body vessel which causes narrowing of the vessel, or which can lead to complete blockage (or occlusion), which leads to restriction or cessation of blood flow through this vessel.
Within the vasculature, it is not uncommon for a stenosis to form at a vessel bifurcation. A bifurcation is an area of the vasculature or other portion of the body where a first (or parent) vessel is bifurcated into two or more branch vessels. Where a stenotic lesion or lesions form at such a bifurcation, the lesion(s) can affect only one of the vessels (i.e., either of the branch vessels or the parent vessel) two of the vessels, or all three vessels.
Implantable medical devices, such as stents, are well known, and may be designed for treatment at vessel bifurcations. Stents are implantable devices which are introduced percutaneously, delivered transluminally to the treatment site in a reduced diameter profile, and once in position, are radially expanded to an enlarged diameter. Stents may be implanted in a variety of body lumens or vessels such as within the vascular system, urinary tracts, bile ducts, fallopian tubes, coronary vessels, secondary vessels, etc. Stents may be used to reinforce body vessels and to prevent restenosis following angioplasty in the vascular system. They may be self-expanding, expanded by an internal radial force, such as when mounted on a balloon, or a combination of self-expanding and balloon expandable (hybrid expandable).
A stent is typically delivered using a stent delivery device, such as a stent delivery catheter. In one common technique, the stent is crimped down to its delivery position over an expandable member, which is disposed at the distal end of the delivery catheter. The delivery catheter, with the expandable element and the stent disposed thereon, is advanced to the treatment site, wherein the balloon and the catheter are expanded, the expandable member deflated and withdrawn, leaving the stent deployed at the site.
Stents for use at vessel bifurcations may have a variety of configurations including, for example, segmented structures which include a primary branch and at least one secondary branch which is positioned adjacent to and/or partially within the primary branch. These segmented systems may employ multiple catheters and/or balloons to deploy all of the stent segments.
Other bifurcated stents include single structure stents wherein the stent is comprised of a trunk with two or more branches extending therefrom.
Still other stent configurations employ a single substantially tubular stent which has a specialized side-branch opening through which an additional stent or structural component may be deployed. Many of these systems employ a stent delivery assembly having a dual-balloon system for deployment of the main and the side-branch of the bifurcation stent.
In any case, it is desirable also to have delivery systems and components thereof, including the expandable members, to be configured for efficient and accurate deployment of these such stents at vessel bifurcations.
There remains a need in the art for improved delivery systems and components thereof, for delivery of stents at vessel bifurcations.
The information described above is not intended to constitute an admission that such information referred to herein is “prior art” with respect to this invention.
Without limiting the scope of the invention a brief summary of some of the claimed embodiments of the invention is set forth below. Additional details of the summarized embodiments of the invention and/or additional embodiments of the invention may be found in the Detailed Description of the Invention below.